Can the ESA Address the Threats of Atmospheric Nitrogen Deposition? Insights from the Case of the Bay Checkerspot Butterfly

By Zdravka Tzankova, Dena Vallano, & Erika Zavaleta

The Bay Checkerspot Butterfly reached its threatened status largely as a result of habitat loss through development. The species now benefits from the habitat protection powers of the Endangered Species Act, yet the biggest new hazard to the survival of remaining Bay Checkerspot Butterfly populations may come from atmospheric nitrogen deposition. Driven by combustion and agricultural emissions, such deposition is an important cause of change in ecosystem structure and function, including potentially critical changes in the remaining Bay Checkerspot Butterfly habitat. We use the Bay Checkerspot Butterfly case to examine whether the Endangered Species Act, as it currently stands, is capable of protecting endangered species from the newly appreciated, remote-origin threat of nitrogen deposition. We employ legal analysis that builds on relevant case law to determine whether the limitations
on harmful activities as set by sections 7 and 9 of the Endangered Species Act can be applied to the emissions that cause nitrogen deposition. As part of the analysis, we juxtapose our case with a similar case that has become quite salient in recent discussions of conservation law: the case for using the Endangered Species Act to help control greenhouse gas emissions.

Our findings leave us cautiously optimistic that the take and jeopardy prohibitions of the Endangered Species Act could be fruitfully leveraged against existing federal and state air quality and emission control programs to help improve the protection of nitrogen-sensitive species and ecosystems.